Interdomain routing determines the routes for delivering packets between two nodes that belong to different autonomous [network] systems (ASs) through border gateways. The AS-level Internet topology can be established using border gateway protocol (BGP) announcements, but determining the routing policies used inside of the AS remains abstract because each AS has a private policy. This abstract AS behavior makes it hard to ensure some engineering values, such as route diversity, efficiency, and so on.

The motivation of this paper is to unveil the unknown behaviors of ASs by conducting a survey on routing policies taken by AS operators. The survey includes 12 interesting questions revealing the respondent’s policy about next-hop selection, export coverage, consistency, minimum route advertisement interval (MRAI) timer, security, and billing models. The implication of each response is explained in detail.

As pointed out in the paper, a limitation is that it might include a biased view due to the limited number of respondents. Also, most questions are relevant to transit networks rather than stub networks. Since transit network operators and stub network operators have different interests, a further study with more questions relevant to stub networks should be performed in a future work.